The discussion of any work, publications, sales, or activity anywhere in this submission, including in any documents submitted with this application, shall not be taken as an admission that any such work constitutes prior art. The discussion of any activity, work, or publication herein is not an admission that such activity, work, or publication existed or was known in any particular jurisdiction.
Microfluidic cell culture is an important technology for applications in drug screening, tissue culturing, toxicity screening, and biologic research and can provide improved biological function, higher-quality cell-based data, reduced reagent consumption, and lower cost. High quality molecular and cellular sample preparations are important for various clinical, research, and other applications. In vitro samples that closely represent their in vivo characteristics can potentially benefit a wide range of molecular and cellular applications. Handling, characterization, culturing, and visualization of cells or other biologically or chemically active materials (such as beads coated with various biological molecules) has become increasingly valued in the fields of drug discovery, disease diagnoses and analysis, and a variety of other therapeutic and experimental work.
Numerous aspects related to microfluidic systems, devices, methods and manufacturing are discussed in the above-referenced and related patent applications. While no particular limitations should be read form those applications into any claims presented herein, these incorporated documents provide useful background material related to specific embodiments.
One area of interest in cellular assay systems are assays that are able to determine characteristics of cellular migration. Such assays are important in characterization of various types of malignant cells and also in characterization of other cells under various stimulations.
Some assays using microchambers or microfluidics have been proposed. Other systems use standard culture plates with various barrier inserts to attempt to detect cellular invasion. Currently available systems, however, have failed with regard to a number of aspects necessary for ease-of-use, high-throughput, or automated applications.
Other publications and/or patent documents that discuss various strategies related to cell culture using microfluidic systems and related activities include the following U.S. patent applications and non-patent literature, which, along with all citations therein, are incorporated herein by reference for all purposes. A listing of these references here does not indicate the references constitute prior art.    Cytoplex, Inc. U.S. Pat. No. 6,653,124 “Array-based microenvironment for cell culturing, cell monitoring and drug-target validation.”    Cellomics, Inc. U.S. Pat. No. 6,548,263 “Miniaturized cell array methods and apparatus for cell-based screening.”    Fluidigm, Inc. Published Application 20040229349 (Nov. 18, 2004) “Microfluidic particle-analysis systems.”